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Tytuł:
Osteoderm histology of Late Pleistocene cingulates from the intertropical region of Brazil
Autorzy:
Da Costa Pereira, P.V.L.G.
Victer, G.D.
Porpino, K.O.
Bergqvist, L.P.
Powiązania:
https://bibliotekanauki.pl/articles/945892.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
osteoderm
histology
Late Pleistocene
Pleistocene
Cingulata
mammalia
Glyptodontidae
Pachyarmatherium
paleohistology
intertropical region
Brazil
Opis:
During the Late Pleistocene, several possibly endemic cingulate species, known mostly from isolated osteoderms, carapace fragments, and caudal tubes, coexisted in the Brazilian Intertropical Region. Here, we describe the osteoderm microstructure of Pachyarmatherium brasiliense, as well as the glyptodonts Panochthus greslebini, Panochthus jaguaribensis and Glyptotherium sp., in order to provide additional species-diagnostic characters and shed light on their evolutionary relationships. Pachyarmatherium brasiliense lacks several derived features shared by glyptodonts and pampatheres, such as extensive bone remodeling, fibers arranged in large bundles, and relatively poorly developed layers of compact bone, thus supporting its exclusion from glyptodonts as suggested by a recent cladistic study. The osteoderm histology of P. greslebini resembles that of other species of Panochthus (e.g., Panochthus frenzelianus). By contrast, the presence of relatively thick layers of compact bone, the configuration and size of resorption areas, the absence of randomly oriented lateral fiber bundles, and the absence of an intermediary region between the compact and trabecular bone potentially support the exclusion of Panochthus jaguaribensis from the genus. Finally, osteoderms of the Brazilian specimens of Glyptodontinae share histological features with Glyptotherium floridanus, rather than Glyptodon, thus reinforcing their assignment to Glyptotherium. These results highlight the relevance of histological osteoderm characters in cingulate systematics, ands call for further and more comprehensive studies.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 3; 543-552
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertebrate paleoecology of the late Campanian (Cretaceous) Fruitland Formation, San Juan Basin, New Mexico (USA)
Autorzy:
Spencer, G.L.
Mateer, N.J.
Powiązania:
https://bibliotekanauki.pl/articles/23423.pdf
Data publikacji:
1983
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Sediments of the Fruitland Formation in northwestern New Mexico represent a delta plain that prograded northeastward over the retrating strandline of the North American epeiric seaway during the late Campanian. Fruitland fossil vertebrates are fishes, amphibians, lizards, a snake, turtles, crocodilians, dinosaurs (mostly hadrosaurs and ceratopsians) and mammals. Autochthonous fossils in the Fruitland Formation represent organisms of the trophically-complex Parasaurolophus community. Differences in diversity, physical stress and life-history strategies within the Parasaurolophus community fit well the stability-time hypothesis. Thus, dinosaurs experienced relatively low physical stress whereas fishes, amphibians, small reptiles and mammals experienced greater physical stress. Because of this, dinosaurs were less likely to recover from an environmental catastrophe than were smaller contemporaneous vertebrates. The terminal Cretaceous extinctions selectively eliminated animals that lived in less physically-stressed situations, indicating that the extinctions resulted from an environmental catastrophe.
Źródło:
Acta Palaeontologica Polonica; 1983, 28, 1-2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Italy’s largest snake: Redescription of Palaeophis oweni from the Eocene of Monte Duello, near Verona
Autorzy:
Georgalis, G.L.
Del Favero, L.
Delfino, M.
Powiązania:
https://bibliotekanauki.pl/articles/2082204.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Squamata
Serpentes
Palaeophis
Paleogene
Europe
Italy
Opis:
We here redescribe Palaeophis oweni, an almost neglected species of palaeophiid snakes from the Eocene of Monte Duello, northeastern Italy. Despite having been described since the 19th century and being the only known named species of its genus from Mediterranean Europe, P. oweni has so far received only minor and sporadic attention in the literature. The only as yet available information for this species was the original lithograph accompanying its brief, 1881 description. We here provide photographs and detailed description of the type and only known material for the first time, designate a lectotype, and clarify certain nomenclatural issues, as well as inaccuracies in the original lithograph. We distinguish certain features in its vertebral anatomy that allow us to treat P. oweni as a valid species and provide an emended diagnosis. Nevertheless, we highlight that a comprehensive reassessment of the nominal species of Palaeophis from the Eocene of the United Kingdom is essential in order to decipher with certainty the validity and distinctiveness of the Italian form. Palaeophis oweni represents the largest snake known from the Italian fossil record.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 3; 523-533
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New specimen of the rare requiem shark Eogaleus bolcensis from the Bolca Lagerstätte, Italy
Autorzy:
Conte, G.L.
Trevisani, E.
Guaschi, P.
Fanti, F.
Powiązania:
https://bibliotekanauki.pl/articles/2082229.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Chondrichthyes
Carcharhinidae
Triakidae
Eogaleus
Galeorhinus
Von Bertallanfy Growth Function
age classes
Eocene
Europe
Opis:
A rare carcharhinid specimen (slab and counter-slab, MSNPV 24625-24626) from the world-renowned Eocene Bolca locality was recently rediscovered during a restoration project started in 1989 by the Museo di Storia Naturale di Pavia. The individual, the largest Eogaleus bolcensis known from Bolca, is disarticulated and lies in a massive limestone matrix, suggesting its provenience from the Monte Postale site. While assessing its taxonomic status, multiple morphological affinities and ontogenetic trends within the Bolca Carcharhiniformes assemblage where documented. Eogaleus bolcensis is here distinguished from the school shark Galeorhinus cuvieri exclusively according to dermal denticle morphology, suggesting partial overlap of ecologic and trophic niches between the two species. Further, measurements and meristic counts taken on different traits of E. bolcensis (two individuals) and G. cuvieri (five individuals) specimens show high degree of similarities. The ratios “trunk length/total length” and “sum of vertebral centra (head region)/total length” of four complete individuals of the fossil assemblage were averaged and employed to estimates the total length of MSNPV 24625-24626. Here, the total length of MSNPV 24625-24626 is estimated in about 172.1±0.1 cm. The same approach is applied to MCSNV T.311 (E. bolcensis, holotype) and MNHN F.Bol.516 (G. cuvieri, holotype), two partially-preserved fossil individuals from Bolca locality. To support the ontogenetic variability among the Bolca shark assemblage, the age of the fossil individuals was estimated following the Von Bertalanffy Growth Function, using the modern chondrichthyans growth parameters as a reference. Data presented here suggest that all G. cuvieri specimens are juvenile individuals, whereas the E. bolcensis specimens were young-adult.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 3; 547-560
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphometry of the teeth of western North American tyrannosaurids and its applicability to quantitative classification
Autorzy:
Samman, T
Powell, G.L.
Currie, P.J.
Hills, L.V.
Powiązania:
https://bibliotekanauki.pl/articles/21645.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Gross tooth morphology and serration morphology were examined to determine a quantifiable method for classifying tyrannosaurid tooth crowns from western North America. From the examination of teeth in jaws, tyrannosaurid teeth could be qualitatively assigned to one of five types based on the cross−sectional shape of the base of the tooth and characteristics of the mesial carina. A principal component analysis (PCA) revealed that much of the variance in tooth shape was a result of isometry, but some gross morphological variables exhibited strong positive allometry. Non−size associated factors were also important in determining tooth shape, particularly when data on denticle dimensions were considered in the analysis. While PCA identified important factors in variation, PCA ordination plots did not cluster the teeth into distinct, separate groupings based on taxon or bone of origin. The group classification functions determined by discriminant analysis, though not universally successful for classifying unidentified isolated teeth of all tyrannosaurids, do identify bone of origin of adult Albertosaurus, Daspletosaurus, and Gorgosaurus teeth at a statistically acceptable level.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 4; 757-776
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Basicranial morphology and phylogenetic position of the upper Eocene carnivoramorphan Quercygale
Autorzy:
Wesley-Hunt, G D
Werdelin, L.
Powiązania:
https://bibliotekanauki.pl/articles/20392.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Quercygale angustidens is a small, early carnivoramorphan from the upper Eocene of northwest Europe including the Phosphorites du Quercy, France. Although there is extensive material of the genus, very little has been published on the auditory region which is an important character complex for taxonomy and phylogenetic studies. This paper presents a detailed description of the basicranium of an undistorted partial skull of Quercygale. The new data form the basis for a phylogenetic analysis of Quercygale in the context of basal carnivoramorphan interrelationships. Quercygale has a mix of derived and plesiomorphic characters. The promontorium is highly derived, and unlike that of any other “miacoid”. Yet, based on the evidence from surrounding bones the bulla does not appear to be as expanded as in other closely related miacids. In the phylogenetic analysis Quercygale is the sister−taxon to Nimravidae and crown−group Carnivora, and it appears to be the most derived of the stem−group Miacidae. We discuss the implications that the position of Quercygale has on carnivoramorphan phylogenetics.
Źródło:
Acta Palaeontologica Polonica; 2005, 50, 4; 837-846
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new, unusual rhynchonellide brachiopod with a strophic shell from the Sirurian of Iran
Autorzy:
Popov, L.E.
Hairapetian, V.
Pour, M.G.
Modzalevskaya, T.L.
Powiązania:
https://bibliotekanauki.pl/articles/20883.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
A new, unusual rhynchonellide brachiopod Jafarirhynchus alatus assigned to the newly established family Jafarirhynchidae is described from the Silurian (Telychian) of the Boghu Mountains in east-central Iran. It forms a low diversity association with the spiriferide Striispirifer? ocissimus, which exhibits well preserved calcified brachial supports. A strophic shell, well-developed ventral interarea and liberosessile mode of life make this taxon unique among Palaeozoic rhynchonellide brachiopods. In spite of a superficial similarity to spiriferides and the atrypide family Davidsonioidea, Jafarirhynchus retains the typical rhynchotrematoid cardinalia with a septalium supported by the median septum, a septiform cardinal process and long, raduliform crura. It is considered as an offshoot of the local lineage, which includes two successive species of Stegocornu (family Rhynchotrematidae) which proliferated in Central Iran and adjacent Afghanistan during Aeronian time.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Early Triassic gladius associated with soft tissue remains from Idaho, USA-a squid-like coleoid cephalopod at the onset of Mesozoic Era
Autorzy:
Doguzhaeva, L.A.
Brayard, A.
Goudemand, N.
Krumenacker, L.J.
Jenks, J.F.
Bylund, K.G.
Fara, E.
Olivier, N.
Vennin, E.
Escarguel, G.
Powiązania:
https://bibliotekanauki.pl/articles/23235.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
We describe an Olenekian (Early Triassic) “fossil squid” belonging to the oldest complex Mesozoic marine biota collected in the Lower Shale unit of the Lower Triassic Thaynes Group in Idaho, USA. The studied specimen shows a tapered structure embedded in a cylindrical soft body. Morphological, ultrastructural and geochemical features of the specimen suggest that it corresponds to an internally-shelled cephalopod exhibiting a tapered micro-laminated gladius with rachis, narrow median and lateral fields and a large conus; a pair of posterior large fin-supported cartilages and fins; ventral and dorsal mantle band-shape structures, the dorsal one being cartilaginous; mantle patches; a stomach containing undigested arm-hooks and sheet-like pieces of potential flooded ink. Coupled SEM/EDS analyses show that (i) arm-hooks and ink were pseudomorphed by nanoparticles (less than 0.6 mm in diameter) of carbon, (ii) gladius and soft tissues were substituted by granules of calcium phosphate, (iii) cartilage canalicula’s were partially filled with calcium phosphate grains and crystals of Zn- and S-containing minerals. The specimen was hence probably fossilized due to metabolism of P- and C-accumulating bacteria. Based on this specimen, Idahoteuthis parisiana Doguzhaeva and Brayard gen. et sp. nov. and Idahoteuthidae Doguzhaeva and Brayard fam. nov. are erected. This family is characterized by an elongated, cylindrical, dorsally cartilaginous muscular mantle; well-developed, about 0.2 mantle length, rounded anteriorly and acute posteriorly, fin-supported cartilages and similarly shaped two fins at conical mantle termination, and thin slender gladius with narrow median and lateral fields, rachis and breviconic conus. This family assumedly falls in Myopsida (Decabrachia). A streamlined body, large fin-supported cartilages and eroded arm-hooks in the stomach of Idahoteuthis Doguzhaeva and Brayard gen. nov. suggest that this was a maneuverable cannibal predator that dwelled in the subequatorial shallow sea of the west coast of Pangaea.
Źródło:
Acta Palaeontologica Polonica; 2018, 63, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An unusual trackway of a possibly bipedal archosaur from the Late Triassic of the Sichuan Basin, China
Autorzy:
Xing, L.
Peng, G.
Marty, D.
Ye, Y.
Klein, H.
Li, J.
Gierlinski, G.D.
Shu, C.
Powiązania:
https://bibliotekanauki.pl/articles/22572.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
The Longguan dinosaur tracksite in the Sichuan Basin (China) is described. It is located in the uppermost part of the Upper Triassic Xujiahe Formation and displays a single, unusual trackway consisting of 19 deeply impressed pes imprints. All tracks have suffered from erosion over many years of exposure, but they still reveal interesting details such as conspicuous elongated grooves, interpreted here as toe and claw drag marks. The trackmaker, a medium-sized archosaur, was walking in a thick and relatively soft layer of sand. The elongated, oval shape of the footprints resembles the ichnogenus Eosauropus from North America and Europe, assigned to facultative bipedal sauropodomorphs. The Chinese track differs by inward rotation of the footprints toward the midline, whereas in Eosauropus, these are turned strictly outward. Other ichnotaxa and possible trackmakers are discussed, but presently, a distinct assignment cannot be given. The Longguan trackway enlarges the scarce footprint record from the Triassic of China.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New artiodactyl ruminant mammal from the Late Oligocene of Pakistan
Autorzy:
Metais, G
Antoine, P.O.
Marivaux, L.
Welcomme, J.L.
Ducrocq, S.
Powiązania:
https://bibliotekanauki.pl/articles/20876.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Ruminantia
ruminant
Palaeohypsodontus zinensis
mammal
Bovidae
Mammalia
artiodactyl ruminant
Oligocene
Pakistan
Late Oligocene
paleontology
Opis:
Dental and postcranial material of the bovid−like ruminant Palaeohypsodontus zinensis sp. nov. is reported from the Oligocene of the Bugti Hills (Balochistan, Pakistan). This finding extends the geographic distribution of this dentally highly derived ruminant, which was previously restricted to the early Oligocene of Mongolia and China. The inclusion of Palaeohypsodontus within the Bovidae is disputed on the basis of astragalus characters, and the taxonomic status of the Oligo−Miocene Eurasian bovid−like ruminants is briefly discussed. It is concluded that the assignment of Palaeohypsodontus to the Bovidae would be premature. More dental and postcranial material of this genus as well as additional fossils of early bovids are necessary to shed new light on the phylogenetic relationships within the first representatives of that family in Eurasia.
Źródło:
Acta Palaeontologica Polonica; 2003, 48, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Triassic eucynodont Candelariodon barberenai revisited and the early diversity of stem prozostrodontians
Autorzy:
MARTINELLI, AGUSTÍN G.
BENTO SOARES, MARINA
DE OLIVEIRA, TÉO VEIGA
RODRIGUES, PABLO G.
SCHULTZ, CESAR L.
Powiązania:
https://bibliotekanauki.pl/articles/945630.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
cynodontia
probainognathia
prozostrodontia
dinodontosaurus assemblage zone
south america
brazi
Opis:
The dental anatomy of Candelariodon barberenai from the Dino donto saurus Assemblage Zone (Pinheiros-Chiniquá Sequence, Santa Maria Supersequence, late Ladinian–early Carnian) of south Brazil, is redescribed. Candelariodon was originally classified as Eucynodontia incertae sedis and our analysis recovered this taxon deeply nested within Probainognathia, as the sister taxon of Potheriodon plus Prozostrodontia. The lower postcanine dentition of Candelariodon has several apomorphies shared with Prozostrodon, Santacruzgnathus, Brasilodon/Brasilitherium, and some basal mammaliaforms (Morganucodon, Megazostrodon), such as a lingual cingulum with discrete cusps e and g and two distinct morphologies in the tooth row. The reinterpretation of Candelariodon as a probainognatian cynodont more derived than Probainognathus and the rich Brazilian fossil record document an important adaptive radiation of non-mammaliaform prozostrodontians and closely related forms prior to the origin of the mammaliaform clade.
Źródło:
Acta Palaeontologica Polonica; 2017, 62, 3; 527-542
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lingulate brachiopods from Lower Ordovician [Tremadoc] chalcedonites, Holy Cross Mountains, Poland
Autorzy:
Holmer, L E
Biernat, G.
Powiązania:
https://bibliotekanauki.pl/articles/19951.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Lingulata
paleobiology
Lower Ordovician
Polska
brachiopod
Ordovician
Holy Cross Mountains
Brachiopoda
Opis:
Lingulate brachiopods from chalcedonites of Tremadoc age are redescribed based on new material from the Holy Cross Mountains, Poland. The fauna includes 18 species, of which Elliptoglossa polonica and Siphonotretella popovi are new. The enigmatic Orbiculoidea? subovalis Biernat is redescribed as a species of the recently erected aberrant paterulids Diencobolus Holmer, Popov, Koneva, and Bassett. The fauna includes also Acrotreta dissimilis (Biernat), ?Ditreta dividua Biernat, Semitreta maior Biernat, Eurytreta minor Biernat, Mamatia retracta (Popov), Orbithele ceratopygarum (Brøgger), Siphonobolus uralensis (Lermontova), Alichovia analogica Biernat, Pomeraniotreta sp., Akmolina sp., Rowellella sp., Acanthambonia sp. A, Acanthambonia? sp. B, Leptembolon cf. lingulaeformis (Mickwitz), and the earliest known species of Eoconulus. Most of the recorded lingulate species are endemic, but a significant number are now known also from eastern Kazakhstan and the South Urals, as well as from the Tremadoc of Sweden and Norway.
Źródło:
Acta Palaeontologica Polonica; 2002, 47, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Earliest laurasian sauropod eggshells
Autorzy:
Garcia, G
Marivaux, L.
Pelissie, T.
Vianey-Liaud, M.
Powiązania:
https://bibliotekanauki.pl/articles/22561.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
megaloolithid egg shell
Middle Jurassic
Bajocian
Quercy area
France
Sauropoda
fossil egg
paleontology
Opis:
Megaloolithid eggshells, known from many Cretaceous deposits since 19th century, are now recognized as remnants of sauropod dinosaurs. Our paper reports the discovery of megaloolithid egg remains from the Middle Jurassic (Bajocian) of the Quercy area (southwestern France). The new Jurassic ootaxon differs from related Cretaceous oospecies in having unusually thin shells. Even Megaloolithus aureliensis, the thinnest Cretaceous megaloolithid from France is three times thicker than the Jurassic eggshells. The cladistic analysis of ootaxa reveals a peculiar point in contradiction with the phylogenetic results based on skeletal remains: the Megaloolithidae belonged to sauropod dinosaurs, which appear to be the sister group of the hadrosaur eggs (Spheroolithidae oofamilly). This result could indicate a significant amount of homoplasy in the evolution of eggshell structures, depending strongly on the incubation environment (particularly for some characters as ornamentation, pore openings and pore canals), the reproductive physiology and the oviduct function. The Bajocian eggshells might represent the earliest offshoot of the Megaloolithidae oofamily and represent the earliest sauropod eggshell record known from the deposits of Laurasia supercontinent.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Camenellan tommotiids from the Cambrian Series 2 of East Antarctica: Biostratigraphy, palaeobiogeography, and systematics
Autorzy:
Claybourn, T.M.
Skovsted, C.B.
Betts, M.J.
Holmer, L.E.
Bassett-Butt, L.
Brock, G.A.
Powiązania:
https://bibliotekanauki.pl/articles/2082288.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Tommotiida
Dailyatia
biostratigraphy
palaeobiogeography
Cambrian
Central Transantarctic Mountains
Opis:
Cambrian Series 2 shelly fossils from thick carbonate successions in East Antarctica have received limited systematic treatment through the 20th century. Described here are the East Antarctic camenellan tommotiids from the Shackleton Limestone in the Central Transantarctic Mountains and the Schneider Hills limestone in the Argentina Range. This material comes from both newly sampled collections and incompletely described material from older collections. The assemblage supports correlation to the Dailyatia odyssei Zone and Pararaia janeae Trilobite Zone of South Australia, with the newly examined specimens of Dailyatia decobruta from the Shackleton Limestone providing direct correlation to the Mernmerna Formation of the Ikara-Flinders Ranges and White Point Conglomerate of Kangaroo Island. These East Antarctic assemblages include five species referred to Dailyatia, in addition to an undetermined kennardiid species and fragments of the problematic Shetlandia multiplicata. The results further corroborate the notion that fossiliferous carbonate clasts found on King George Island were sourced from the same carbonate shelf as the Shackleton Limestone, with the taxon S. multiplicata found in both units. The Schneider Hills limestone in the Argentina Range has yielded sclerites of Dailyatia icari sp. nov., currently only known from this location.
Źródło:
Acta Palaeontologica Polonica; 2021, 66, 1; 207-229
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A unique late Eocene coleoid cephalopod Mississaepia from Mississippi, USA: New data on cuttlebone structure, and their phylogenetic implications
Autorzy:
Doguzhaeva, L.A.
Weaver, P.G.
Ciampaglio, C.N.
Powiązania:
https://bibliotekanauki.pl/articles/23390.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
A new family, Mississaepiidae, from the Sepia–Spirula branch of decabrachian coleoids (Cephalopoda), is erected on the basis of the following, recently revealed, morphological, ultrastructural and chemical traits of the cuttlebone in the late Eocene Mississaepia, formerly referred to Belosaepiidae: (i) septa are semi−transparent, largely chitinous (as opposed to all other recorded cephalopods having non−transparent aragonitic septa); (ii) septa have a thin lamello−fibrillar nacreous covering (Sepia lacks nacre altogether, Spirula has fully lamello−fibrillar nacreous septa, ectochochleate cephalopods have columnar nacre in septa); (iii) a siphonal tube is present in early ontogeny (similar to siphonal tube development of the Danian Ceratisepia, and as opposed to complete lack of siphonal tube in Sepia and siphonal tube development through its entire ontogeny in Spirula); (iv) the lamello−fibrillar nacreous ultrastructure of septal necks (similar to septal necks in Spirula); (v) a sub−hemispherical protoconch (as opposed to the spherical protoconchs of the Danian Ceratisepia and Recent Spirula); (vi) conotheca has ventro−lateral extension in early ontogenetic stages (as opposed to Sepia that has no ventro−lateral extention of the conotheca and to Spirula that retains fully−developed phragmocone throughout its entire ontogeny). Chitinous composition of septa in Mississaepia is deduced from (i) their visual similarity to the chitinous semi−transparent flange of Sepia, (ii) angular and rounded outlines and straight compressive failures of the partial septa and mural parts of septa similar to mechanically−damaged dry rigid chitinous flange of Sepia or a gladius of squid, and (iii) organics consistent with −chitin preserved in the shell. The family Mississaepiidae may represent a unknown lineage of the Sepia–Spirula branch of coleoids, a conotheca lacking a nacreous layer being a common trait of the shell of this branch. However, Mississaepiidae is placed with reservation in Sepiida because of similarities between their gross shell morphology (a cuttlebone type of shell) and inorganic−organic composition. In Mississaepia, as in Sepia, the shell con− tains up to 6% of nitrogen by weight; phosphatised sheets within the dorsal shield may have been originally organic, like similar structures in Sepia; accumulations of pyrite in peripheral zones of aragonitic spherulites and in−between the spherulites of the dorsal shield may also indicate additional locations of organics in the shell of living animal.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 32

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